the next instruction just as it would for any standard scalar v3.0B
instruction.
-An explicit instruction is called which can move srcstep and
+An explicit mode of setvl is called which can move srcstep and
dststep on to the next element, still respecting predicate
-masks.
+masks.
In other words, where normal SVP64 Vectorisation acts "horizontally"
by looping first through 0 to VL-1 and only then moving the PC
used (branch instruction) which completes a series of
Vector operations.
+```svstep``` mode is enabled when vf=1, vs=0 and ms=0.
+When Rc=1 it is possible to determine when any level of
+loops reach an end condition, or if VL has been reached. The immediate can
+be reinterpreted as indicating which SVSTATE (0-3)
+should be tested and placed into CR0.
+
+* setvl immediate = 1: only VL testing is enabled. CR0.SO is set
+ to 1 when either srcstep or dststep reach VL
+* setvl immediate = 2: also include inner middle and outer
+ loop end conditions from SVSTATE0 into CR.EQ CR.LE CR.GT
+* setvl immediate = 3: test SVSTATE1
+* setvl immediate = 4: test SVSTATE2
+* setvl immediate = 5: test SVSTATE3
+
# Pseudocode
// instruction fields: